The present invention relates to a novel stress-luminescent material of high luminosity which is a material capable of emitting intensive luminescence when stressed by receiving a mechanical force as well as a method for the preparation of such a stress-luminescent material and a method for obtaining luminescence by using the stress-luminescent material.
It is well known in the prior art that certain materials called a phosphor exhibit luminescence which is a phenomenon to emit visible light at or in the vicinity of room temperature when the material receives stimulation from outside. Phosphor materials capable of emitting luminescence are widely employed in lighting devices such as fluorescent lamps and displays such as cathode ray tubes (CRT).
The stimulation from outside to cause the phenomenon of luminescence is given conventionally by ultraviolet light, electron beams, X-rays, ionizing radiations, electric fields, chemical reactions and so on. There are found, however, very few reports that certain materials can emit luminescence when stressed by receiving stimulation from outside such as a mechanical force. Such a material is referred to as a stress-luminescent material hereinafter.